136 Flies [CH. 
about 3 inch in length and are of a yellow and black 
colour. The thorax has three black longitudinal 
markings on its back (see Fig. 41C). This fly has two 
broods every year. The first brood appear in May and 
lay their eggs on the sheathing leaves of the plants. 
The maggot which hatches from one of these eggs 
pierces its way until it reaches the stem. Here it 
commences to feed on the lower portion of the ear, and 
usually eats its way down the stem, making a groove 
to the first joint. In the groove or in the leaves 
surrounding the ear it changes into a pupa in July. 
Flies hatch out from these in August and September 
and lay their eggs on wild grasses or winter corn. 
The maggots of this brood may be found on grasses in 
November. They eventually give rise to the first 
brood next season in May and June. 
Remedial Measures. 
Once this fly has established itself in our barley 
plants we can do little to stop any loss. Barley on 
poor soils suffers most, as on soils in good heart the ears 
are often able to push their way through the leaves 
even after they are attacked. If the attack is found 
out in its early stages the application of a quick-acting 
nitrogenous manure, such as sodium nitrate, may be 
useful. It has been found that barley sown before 
March 20th rarely suffers from attacks of this fly, but 
that when sown in April it may suffer very considerably. 
The best means of prevention then lies in getting the 
barley in early so that the young plants are well 
established before the flies hatch out. The land should 
be kept as clean as possible so that the fly may be 
